Formula to count unique instances

I have a workbook with two worksheets in it. Each sheet has col A, B, C, D with the same headers. The first sheet has rows and rows of data with the data info in these columns (could be unique or repetitive) yet other unique data in the rest of the columns on the file. This first sheet shows the details of each transaction.

The second sheet is used to sum up those transactions. I need a formula for sheet 2 column D that will count the unique items in sheet 1 column D if the first three columns on each sheet match. Example below:

Sheet 1:
Col A Col B Col C Col D Col E
Set 1 Batch 1 Item 1 Unit 1 $100
Set 1 Batch 1 Item 1 Unit 2 $100
Set 1 Batch 2 Item 1 Unit 1 $100
Set 1 Batch 1 Item 2 Unit 1 $100
Set 1 Batch 1 Item 2 Unit 1 $125
Set 1 Batch 1 Item 2 Unit 2 $125
Set 1 Batch 1 Item 2 Unit 3 $125


Sheet 2:
Col A Col B Col C Col D
Set 1 Batch 1 Item 1 need formula here that will tell me how many unique units are in sheet 1 Column D that also have Set 1, Batch 1, and Item 1 in the first 3 columns respectively.

Thanks

Tony,

Can you explain "-ROW(D2)+1),1))"
Since my data is on 2 sheets and I'm looking at the entire columns of data on Sheet 1, I'm not sure why this section of the formula only references one cell on Sheet 1 Column D.
Thanks.